Refrigerating apparatus



March 11, 1941. H. v. FRIEDMAN REFRIGERATING APPARATUS Filed Feb. 11, 1939 INVENTOR H V'fiz'ediuan $351.82.; I ATTORNEY Patented Mar. 11,1941 2,234,372

UNITED STATES PATENT oFFics- BEFBIGEBATING APPARATUS Hamid V. Friedman, Las Vegas, Nev., assignor of one-half to Alma M. Friedman, Dallas, Tex.

Application February 11, 1939, Serial No.'255,950 5 Claims. (Cl. 62-915) This invention relates in general to improved Another object of the invention is to provide refrigerating apparatus for commercial or donovel means to accomplish heat transfer from the mestic use, and in particular the invention is diliquid in the cooling coil system to the gas prorected to an improvement in that type of reduced by the sublimation of the dry ice; such 5 frigerating apparatus in which a low temperaheat transfer being accomplished at a point ima ture substance such as solidified carbon dioxide mediately below the body of refrigerant as well is used as the cooling medium, and which subas at a point thereabove so as to assure maximum stance is characterized by the fact that it subefficiency. limates during the'heat exchange process. For A further object is to control the rate of subthe purpose of this specification, such substances limation of the dry ice, and the consequent re- 1 will be referred to as dry ice." frigerating or heat exchange activity, by regulat- Solidified gas has been already widely used for ing the gas pressure in the insulated chamber refrigeration, and one known application isthat containing the dry ice, and by providing means of placing the dry ice directly in the space to be to vary the distance between the body of dry refrigerated, and allowing the process of subice and adjacent portion of the cooling coil sys- 15 limation to continue as longand at such rate tem. V

as heat is supplied from the surroundings by, It is also objects of the invention to provide radiation and convection. To promote more positive and yet safe means for the expansion uniform temperature control, forced circulation and contraction of the liquid in the cooling coil of air over the refrigerant has been used. Other system and without entry of outside air or the devices, such as setting up gravity air circulation production of a vacuum: and to provide for the over the refrigerant in an upper chamber to cool venting of any excess gas pressure from the dry a p e in lower mber, and the use of variice heat and exchange system whereby to avoid able dampers and orifices to control the circuladamage to the apparatus.

tion have been used. In an effort to provide A further object of the invention is to produce 25 greater control over the rate of sublimation and a, simple and inexpensive device and yet one qu t refrigeratio q ds 'of a volatile which will be exceedingly effective for the purpose nature have been condensed and re-evaporated for which it is designed. th ou h a sy m f r is t pip n wi dry These objects I accomplish by means of such ice s the P y mediumhe o v us structure and relative arrangement of parts as 30 l y i h m pplications of dry ice to d will fully appear by a perusal of the following has been either a lack of adequate control over specification and im the rate and intensity of the refrigeration, or an In the drawing similar characters of reference over complication of thermostatic appliances indicate corresponding parts in the several views:

..5 which do not function well at the very low tem- Figure l is adiagrammatic elevation of the apperatures that exist in the dry ice system. paratus.

However, due to itsv desirable refrigerating Figure 2 is an enlarged, fragmentary elevation, qualities, there is a demand for the application in section, of the gas actuated intermittent flow of dry ice refrigeration in perishable produce pump in the cooling coil system.

- 40 transporting vehicles, and the like. Referring now more particularly to the char- 7 It is therefore one object of this invention to acters of reference on the drawing. the numeral provide dry ice refrigerating apparatus which I indicates a containen formed with an internal includes a system which is self-operating, 'posichamber 2, there being a gas tight door 3 which I tive and reliable, free from complication, and yet permits access to the chamber. The area behighly efficient; efilciency being an essential due tween the chamber 2 and container I is heavily to the relatively high cost .of production of the insulated as at 5. A cake I of dry ice is supdry ice. ported in the chamber, in spaced relation to the Another object of the invention is to provide a walls thereof, on a perforate platform 8; this refrigerating apparatus of the type described platform being mounted, as at I, for vertical ad- 9 wherein. is included a closed cooling coil system 'iustment. If desired, mechanism may be. in-

arranged in unique combination with a dry ice corporated to effect such'vertical adjustment from heat exchange system; the gas resulting from the exteriorly of container l. Y sublimation of the dry ice being held under pres- A horizontally disposedv heat exchange coil 9 sure and'used to circulate a liquid in the cooling is mountedin the chamber 2 below theperforate coil system. V platform 8, whileanother heat exchange coil 9, 55

of the fin type is disposed in the chamber above the cake of dry ice; these two coils being connected together at one end by a pipe Ill. The other end of the lower coil 8 is connected with a pipe I I which leads out of container I into the ice box l2 or like enclosure whose interior is to be cooled; a heat exchange coil I3 being mounted in the box l2 and connected at one end with pipe ll, while the other end of coil I3 is connected with a pipe 14 leading out ofbox l2 and discharging into an enclosed expansion tank i5 and at a point adjacent the top thereof.

A pipe l6 extends from the bottom of the tank I! to the gas actuated intermittent flow pump, indicated generally at H, and a check valve I 8 is interposed in such pipe l6 and opens toward the pump II. A pressure relief valve unit l9 connects with the top of the expansion tank and opens to the atmosphere. The pump I1 is in the nature of a pulsometer and will be described in detail hereinafter. A return line or pipe 29 extends from the bottom of pump H to the re- ,maining end of the upper coil 9 in chamber 2; there being a check valve 21l in pipe 20 and opening towards coil 9.

A gas delivery pipe 22 communicates at "one end withthe top of chamber 2 in container 1 and leads therefrom to a Y 22; one branch 220 being connected into the top of pump 11, while the other branch 22b enters box I2 and is connected with a supplementary heat exchange coil 23 mounted .therein. The other end of coil 23 extends out of the box l2 and is there provided with a pressure relief valve 24 which opens to the atmosphere. The branch 2211. has a thermostatic valve 25 interposed therein and controlled by means of an extension tube 28 which runs into box l2 and is there provided with a thermostat unit 21 associated with heat exchange coil I3. A pipe 28 enters the top of the pump in spaced relation to pipe 22a and leads to connection with expansion tank I! adjacent the top and in substantially the same plane as pipe l4.

In detail the gas actuated pump I'I comprises a housing or tank 29 which is formed with an internal horizontal partition30 disposed adjacent butspaced from the top of the tank; theinterior of the housing thus being separated into a relatively large lower chamber 3i and a small upper chamber 32. A transverse wall 33 in the upper chamber forms a separate gas chamber 34. Pipe 22a is in communication with chamber 32 and pipe 28 leads into chamber 34.

Parts'35 and 36, provided with upwardly opening valves3'l and 39 respectively, are formed in partition 30 and provide for controlled communication between upper chambers 32 and 34, and

lower chamber 3|. The valve 31 is opened and.

valve 33 closed simultaneously, or vice versa, by means of a snap action lever unit 39 which is actuated by a float which is slidably mounted Operation In use the container I as well as expansion tank. and pump "may be disposed at a point remote from boxl2'. For example, box [2 may be the enclosed body of a motor vehicle. while the container I, etc., may be mounted on the under frame or the like and thus does not occupy valu-- able space in the cooled or refrigerated body.

The refrigerating process is as follows:

As the cake 5 of dry ice sublimates, the intensely cold gas falls to the bottom of chamber 2 where it effects a heat transfer from the liquid in coil 8 and which liquid is being intermittently circulated through this coil and into the coil l3 in box l2 as will hereinafter appear. After the initial heat exchange'at coil 8, the gas then rises about the sides of the cake 5 of dry ice and passes over the upper coil 9 effecting a further heatexchange. As the liquid in the cooling coil system enters coil 9 first and then drops to coil 8, the

the cake 5 and which curtain of gas serves as an into upper chamber 32 in the pump housing 29.

Liquid in the cooling coil system and specifically from the expansion tank l5 flows through pipe l8 into the lower chamber in pump housing 29 which causes float 40 to rise. As the float reaches the upperend of its limit of travel, the snap action lever unit 39 is tripped, opening valve 31 and closing valve 38. Thereupon gas under pressure flows from chamber 32 into chamber 3| forcing the liquid therein out through pipe 20, which causes a flow in coil 9, pipe l0, coil 8, and thence into pipe Ii and coil l3 in the box l2; an equal portion of liquid being discharged by pipe l4 into expansion tank [5. As the liquid is forced reaches the bottom of the rod 4|, it again trips unit 39 closing .valve 31 and opening valve 39 so that the gas may escape from said chamber 3| and the latter mayagain fill with liquid and the pumping cycle be repeated.

While valve 38 is open the gas remaining in chamber 3i from the previous pumping opera-- tion is displaced through chamber 34 and pipe 28 into expansion tank l5 where it serves as an expansion compensating medium and prevents creation of vacuum and possible entry of air and moisture from the atmosphere into the appara- 'tus.

The spent gas in tank l5 escapes through check valve l9; said valve being set to open outwardly under normal operating pressure of the gas.

The frequency of the pumping cycle is controlled by valve 25, and which valve is actuated thermostatically from thermostat unit 21 which is set to effect opening of valve upon a predetermined rise in temperature at the coil l3 in box l2. The portion of the gas. from pipe 22 which is not passedthrough the pump assembly, as above, flows through pipe 22b and into coil 23 in box l2 where additional heat exchange isaccomplished. Thereafter, such portion of gas is relieved into the atmosphere'by pressure relief valve 24. In practice, all of the exposed pipes, both gas and liquid, will be adequately insulated against heat exchange.

From the foregoing description it will be readily seen that I have produced such a device as substantiallyfulfllls the olfiects of the invention as set forth herein.

[from the chamber 3|, float 40 falls and as it While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention, what I claim as new and useful and desire to secure by Letters Patent is:

1. Refrigerating apparatus comprising, in combination, a chamber to be cooled, a separate gastight chamber adapted to receive a sublimatory refrigerant, a heat exchange coil system including a coil in each of said chambers, a refrigerating liquid in the system, a gas actuated pump interposed in the system, a gas feeding pipe leading directly from the refrigerant chamber to the pump, a valve interposed in said pipe between said refrigerant chamber and said pump, said valve being adapted to positively control the flow of gas through said pipe, and temperature responsive means associated with the coil in the chamber to be cooled and arranged to actuate said valve.

2. In refrigerating apparatus including a closed chamber adapted to receive a. sublimatory refrigerant, means to support a quantity of said being disposed below said space, and a passage to vent the gas resulting from the sublimation of the refrigerant from the top of said chamber.

3. An apparatus as in claim 2 including a horizontal baflle mounted in the chamber some distance, below the top thereof but above said one coil; said bafile forming a separate compartment at the top of the chamber, the battle having an orifice therein between the chamber and said compartment.

4. Refrigerating apparatus comprising a chamher to be cooled, a separate gas tight chamber adapted to receive a sublimatory refrigerant, a heat exchange coil system including a coilin each of said chambers, a pulsometer type gas actuated pump interposed in said system intermediate said chambers, and expansion tank in the system ahead of the pump, a check valve in the system between the expansion tank and the pump and opening toward the latter, another check valve in the system beyond and opening away from the pump, a gas feeding pipe extending from the gas tight chamber to the pump, a valve in said pipe, and temperature responsive means associated with the coil in the chamber .to be cooled and arranged to actuate said valve inthegas feeding pipe.

5. An apparatus. as in 'claim 4 including an other gas flow pipe extending between the pump and expansion tank, whereby theexhaust gas from the pump flows to said expansion tank, and an outwardly opening check valvearranged to vent said exhaust gas from the expansion tank at normal operating pressure but without permitting entry of air into the system.

' HAROLD V. FRIEDMAN. 

